Apparatus for producing aggregates



Oct. 1l, 1932. R. HEDRICK v APPARATUS FOR PRODUCING AGGREGATES Filed May 14, 19150 WEEE..

Patented Oct. 11, 1932 UNITED' STATES RICHARD HEDRICK, F LOS'ANGELES, CALIFORNIA APPARATUS FOB PRODUCING AGGBEGATES Application filed May 14, 1930. Serial No. 452,256.

r bodies of clay that form the aggregates and further, to provide an apparatus whereby the aggregates are constantly agitated and sanded while subjected to heat within the kiln, thereby preventing the baking together of the bodies of clay.

Y Vith the foregoing and other objects in view, my invention consists in certain novel features of construction and arrangement of parts that will hereinafter be more fully described and claimed and illustrated in the accompanying drawing, in which:

Fig. 1 is a longitudinal section of a relatively simple form of apparatus embodying my invention.

2-2 of Fig. 1.

Fig. 3 is a cross section of amodied form of the kiln that may be utilized for producing aggregates.

Referring by numerals to the accompanying drawing, which illustrates al simple form of apparatus that may be utilized for producing aggregates in accordance with my invention, designates a rotary kiln compris- L ing an elongated cylindrical body that may include an outer shell 11 of metal and a lining 12 of fire brick or like fire resistant. This kiln is mounted for rotation on suitable supports 13 and it may be rotated in any suit- .l able manner, preferably by means of a pinion or gear wheel 111 that engages the teeth of a ring gear 15 that is mounted on the kiln.

The slightly elevated end of the retort is closed by a fixed plate 16 having in its upper Y. portion an outlet 17 for the heated air and Fig. 2is a cross section taken on the line gases that pass through the kiln and passing through an opening in the plate 16 is a chute 18 by means of which the small clay bodies that are to be formed into aggregates are delivered into the kiln.

The lower end of the kiln is closed by a fixed plate 19 through the center of which passes a burner tube 2O and formed through the lower portion of this plate is a discharge opening 21 that is controlled by a suitable valve or door 22 and leading from this discharge opening is a chute 23, through whichv the aggregates pass as they discharge from the rotating kiln.

Arranged on the interior of the kiln and extending lengthwise therein is a series of ribs or ledges 24 which, as the kiln rotates, picks up vthe material at the bottom of the kiln and carries the same upwardly to a point where the material by gravity falls from the ribs or ledges and passes downwardly through the heated chamber within the kiln to the bottom thereof,

These ribs or ledges 24 which extend lengthwise of the kiln on the interior surface thereof, are preferably disposed parallel with the axis and, as shown in Fig. 1, I prefer to extend said ribs or ledges from the lower discharge end of the kiln to a point adjacent to or just beyond the longitudinal center of the kiln. In this connection it may be stated that the aggregates or small bodies of clay or the like that are delivered directly from the forming machine into the inlet end of the kiln contain considerable moisture and if they were immediately picked up immediately after their entrance into the kiln and agitated by ribs or ledges, the Wet bodies of claywould assemble and adhere to each other so as to form lumps and this condition should be avoided.

In Fig. 2 I have shown the ribs or ledges with straight flat faces and in Fig. 3 the ribs or ledges are shown curved in cross section so as to form shallow scoops that pick up the aggregates and carry the same to the top of the kiln before dropping the aggregates to the bottom thereof.

In producing aggregates with the apparatus just described the kiln is rot-atedv at-a Gil proper speed and the burner at the lower end of the kiln is lighted so as to heat the in terior thereof.

If by the law of nature, heated air or gases rise, it is evident that the temperature in the lower portion of the space within the kiln is lower than the temperature in the upper portion of said space.

As the interior of the kiln is made plain or comparatively smooth without ribs or ledges, the material passing through the kiln Will travel slowly through the bottom of the space within the kiln and where a relatively high degree of uniformity of the finished product is required, it will be seen that a plain kiln devoid of ribs or ledges will not produce satisfactory results.

In my improved kiln the small bodies or lumps of prepared clay are delivered into the upper end of the kiln through chute 18 and they will travel for a portion of the distance throughout the length of the kiln on the bottom thereof without being carried upward and dropped through the chamber in the kiln during which time the lumps lof clay will become dry without adhering to each other and forming large lumps.

In producing aggregates in my improved apparatus a certain amount of sand is delivered into the kiln with the small bodies or lumps of clay and this sand adheres to the surfaces of the small clay bodies so as to prevent the same from adhering to each other while wet.

The small bodies of clay utilized in the production of aggregates are, previous to their introduction into the kiln, mixed with a certain percent of carbon and under the relatively high heat within the kiln this carbon gives oif gases whichy expand the bodies of clay to several times their original size and imparting to said bodies a cellular structure. As a result the aggregates when used in the manufacture of concrete blocks or the like and composed of a mixture of cement and aggregates, the weight of the finished structure containing the aggregates will be much less than the weight of concrete blocks or the like formed of cement and aggregates such as sand and gravel.

In many lines of buildings relatively light weight cement structures are desirable and therefore aggregates constructed in accordance with my invention may be advantageously employed in the production of this class of work.

A further feature of my improved apparatus is the provision of facilities for permitting a constant expansion of the aggregates while subjected to high temperatures and this result is accomplished by a comparatively lively agitation of the aggregates as they pass through the rear portion of the kiln or while they are being picked up, carried upward and then dropped through the heated chamber in the kiln.

Such active agitation prevents the aggregates at the time of incipient fusion from sticking or bonding to each other and this action is enhanced by the use of the sand which enters the kilm with the aggregates I for, during the lifting and dropping of the aggregates, the sand is Acarried with said aggregates and said sand iscontinuously distributed over the product during the firing action or the application of the high temperatures.

The simple rotation of an old style kiln that is devoid of means for lifting the mass of aggregates and sand from the bottom ofthe kiln will eventually permit all the sand toY settle on the bottom of the kiln, thereby forming a part overwhich the aggregates roll and as a result there will be a high percentage of underburned aggregates, a small percentage well burned and properly processed aggregates and a certain percentage of overburned bonded aggregates which are unfit for use.

In addition to the production of aggregates or gas expanded bodies of Clay or the like, my improved apparatus may be advantage` ouslyutilized for the production of vitrified pebbles of clay or other earthen material and which pebbles may be employed in pebble mills in place of the natural pebbles now used and which latter are expensive due to the lim-V ited supply.

Thus it will be seen that I have provided a relatively simple apparatus for producing aggregates to be used in concrete construction and particularly Where light weight or low spaced gravity structures are desired.

It will be understood that minor changes in the size, form and construction of the various parts of my improved apparatusfor producing aggregates may be made and substituted for those herein shown and described without departing from the spirit of my invention, the scope of which is set forth in the appended claims.

I claim as my invention:

l. In an apparatus for producing aggregates, a rotary kiln provided at one end with an inlet opening and at the opposite end with an outlet opening, a burner at the end of the kiln having the outlet opening and a plurality of ribs projecting inwardly from the wall of the kiln and extending longitudinally thereof and which ribs extend from the end of the kiln having the outlet opening to points adjacent to the longitudinal center of the kiln. i Y

2.` In an apparatus for producing aggregates, a rotary kiln, a lining of refractory material for said kiln and aplurality of `ribs projecting inwardly from the lining of said kiln and extending lengthwise thereof, from n. cb

gni

the discharge end of said kiln to a point adjacent to the longitudinal center thereof.

3. In an apparatus for producing aggregates, an elongated rotary drum provided at one end with an inlet opening and at the opposite end with an outlet opening, a series of longitudinally disposed ribs arranged on the inner face of the circumferential Wall of the drum and extending from the end having the outlet opening to points adjacent to the longitudinal center of the kiln and means for heating the interior of said drum.

4. In an apparatus for (producing aggregates, an elongated rotary rum, rolling supports for said drum, one end of which drum is higher than the other, a lining of refractory material for said drum, fixed heads for the ends of said drum, one of which heads is provided with an inlet opening, the other head zo being provided With an outlet opening, a

burner supported by the head having the outlet opening and a plurality of longitudinally disposed ribs projecting inwardly from the lining of the drum and extending lengthwise thereof from the head having the discharge opening to a point adjacent to the longitudinal center of the drum.

In testimony whereof I affix my signature.

RICHARD HDRICK. 

